Image copyrightAPImage caption Many migrants are being prevented by Macedonian police from crossing into the country

Image copyrightAPImage caption A tent city has sprung up in the Greek border village of Eidomeni

Image copyrightReutersImage caption On Monday, a group of migrants – believed to be from Iran – sewed their lips together in protest

Image copyrightAPImage caption Despite new restrictions and colder weather, migrants are continuing to arrive in Greece as they head to richer EU nations

Hundreds of migrants have been protesting for several days against the decision.

About 2,900 people crossed into Macedonia in the 24 hours before 06:00 (local time) on Monday, down from more than 6,000 on the previous day, the Associated Press news agency quoted local police as saying.

Europe’s border controls have come under renewed scrutiny since the attacks in Paris on 13 November.

At least two of the militants involved had passed through Greece, apparently posing as migrants, early last month.

Balkan countries said last week they would only open their borders to people fleeing countries affected by war such as Syria, Iraq and Afghanistan.

A note on terminology: The BBC uses the term migrant to refer to all people on the move who have yet to complete the legal process of claiming asylum. This group includes people fleeing war-torn countries such as Syria, who are likely to be granted refugee status, as well as people who are seeking jobs and better lives, who governments are likely to rule are economic migrants.